1. Field of the Invention
The present invention relates to a driving circuit of semiconductor-type light source for vehicle lighting device using a semiconductor-type light source as a light source. In addition, the present invention relates to a vehicle lighting device using a semiconductor-type light source as a light source.
2. Description of the Related Art
A driving circuit of semiconductor-type light source for vehicle lighting device of such type is conventionally known (for example, Japanese Laid-open Patent Application No. 2004-34742). Hereinafter, a conventional driving circuit will be described. The conventional driving circuit is provided with: a plurality of light emitting elements (LEDs); a direct current power source for feeding a driving current to the plurality of light emitting elements; and a connector at which a plurality of connection terminals indicating a plurality of electrical resistance values are provided. In addition, the plurality of light emitting elements is adapted to receive a feed of direct current power through a connection terminal that is selected according to its own electrical characteristics.
However, the conventional driving circuit uses a package product such as an SMD as a light emitting element (an LED) and uses the light emitting element as a package product that is classified and ranked on the order of 4 or 5 ranks subsequent to measuring Vf characteristics of the light emitting element after packaged. In addition, the conventional driving circuit is manufactured by connecting a resistor in series to a package product so that a predetermine set current is obtained for each of the light emitting element groups as package products classified and ranked in detail at the time of board fabrication and then setting a resistance constant for each light emitting group of the thus classified and ranked package product. As a result, in the conventional driving circuit, in order to provide a downsized, inexpensive semiconductor-type light source, in a case where a bare-chip light emitting element is used instead of a package product such as an SMD as a light emitting element, it is ineffective and difficult to classify and rank the bare-chip light emitting element subsequent to measuring Vf characteristics of the light emitting element that is in such a bare-chip state.
The present invention has been made in order to solve the above-described problem that, in the conventional light source unit, it is ineffective and difficult to classify and rank the light emitting element subsequent to measuring Vf characteristics of the light emitting elements that are in a bare-chip state.